By weaving some quantum wizardry, A*STAR researchers have achieved something that appears to be a contradiction in terms—using visible light to perform spectroscopy at infrared wavelengths. Even more mysterious is that ...

NASA's Cassini spacecraft looks down at the rings of Saturn from above the planet's nightside. The darkened globe of Saturn is seen here at lower right, along with the shadow it casts across the rings.

An environmentally friendly, efficient and low-cost method for hydrogenation of graphene with visible light has been developed by researchers at Uppsala University and AstraZeneca Gothenburg, Sweden. The research study is ...

Stanford engineers have developed a low-cost, plastic-based textile that, if woven into clothing, could cool your body far more efficiently than is possible with the natural or synthetic fabrics in clothes we wear today.

By fine-tuning the chemical composition of nanoparticles, A*STAR researchers have developed a coating that is promising for fabricating smart windows suitable for tropical countries. Such windows block almost all the infrared ...

Dione reveals its past via contrasts in this view from NASA's Cassini spacecraft. The features visible here are a mixture of tectonics—the bright, linear features—and impact cratering—the round features, which are spread ...

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so ...

Saturn's moons Tethys and Hyperion appear to be near neighbors in this Cassini view, even though they are actually 930,000 miles (1.5 million kilometers) apart here. Tethys is the larger body on the left.

Research at ANSTO has helped to reveal insights into a molecular mechanism for harvesting light in extreme conditions. These insights may ultimately lead to previously inaccessible regions of the electromagnetic spectrum ...

Visible spectrum

The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 790–400 terahertz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function). The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, and purple colors such as magenta are absent, for example, because they can only be made by a mix of multiple wavelengths.

Visible wavelengths also pass through the "optical window," the region of the electromagnetic spectrum that passes largely unattenuated through the Earth's atmosphere. (Blue light scatters more than red light, which is why the sky appears blue.) The human eye's response is defined by subjective testing (see CIE), but atmospheric windows are defined by physical measurement.

The "visible window" is so called because it overlaps the human visible response spectrum. The near infrared (NIR) windows lie just out of human response window, and the Medium Wavelength IR (MWIR) and Long Wavelength or Far Infrared (LWIR or FIR) are far beyond the human response region.

Many species can see wavelengths that fall outside the "visible spectrum". Bees and many other insects can see light in the ultraviolet, which helps them find nectar in flowers. Plant species that depend on insect pollination may owe reproductive success to their appearance in ultraviolet light, rather than how colorful they appear to us. Birds too can see into the ultraviolet (300-400 nm), and some have sex-dependent markings on their plumage, which are only visible in the ultraviolet range.